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2 0 1 4 I l l i n o i s Forest Health Highlights

Prepared by Fredric Miller, Ph.D. IDNR Forest Health Specialist, The Morton Arboretum, Lisle, Illinois

Table of Contents

I. Illinois’s Forest Resources 1

II. Forest Health Issues: An Overview 2-4

III. Exotic Pests 5-8 IV. Plant Diseases 9-11 V. Insect Pests 12-14

VI. Weather/Abiotic Related Damage 14

VII. References 15

I. Illinois’ Forest Resources

Illinois forests have many recreation and wildlife benefits. In addition, over 32,000 people are employed in primary and secondary wood processing and manufacturing. The net volume of growing stock has increased by 40 percent since 1962, a reversal of the trend from 1948 to 1962. The volume of elms has continued to

Figure 1. Illinois Forest Areas

decrease due to Dutch elm disease, but red and white oaks, along with black walnut, have increased by 38 to 54 percent since 1962.

The area of forest land in Illinois is approximately 5.3 million acres and represents 15% of the total land area of the state (Figure 1). Illinois’ forests are predominately hardwoods, with 90% of the total timberland area classified as hardwood forest types (Figure 2). The primary hardwood forest types in the state are oak- hickory, at 65% of all timberland, elm-ash-cottonwood at 23%, and maple-beech which covers 2% of Illinois’ timberland. .

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Figure 2. Major forest types by percent of total timberland. Source: Illinois’ Forest

2005, NRS-29.

MERALD ASH BORER (EAB) TRAP TREE MONITORING PROGAM

With the recent (2006) find of emerald ash borer (EAB) in northeastern Illinois and sub-

sequent finds throughout the greater Chicago metropolitan area, and as far south as

Bloomington/Chenoa, Illinois area, prudence strongly suggests that EAB monitoring is

needed for the extensive ash containing forested areas associated with Illinois state parks,

U.S. Army Corps of Engineers (USACE) lands, and the Shawnee National Forest (SNF).

Beginning in early July, 2008 trap trees were established at USACE lands at Carlyle,

Renwick, and Shelbyville Lakes, Hazlet, Murphysboro, and Giant City state parks, and at

the Garden of the Gods and Lake Glendale recreational use areas in the SNF. EAB trap

trees were established using the USFS EAB trap tree guidelines. Where possible, trees in

full sun were selected and at or near sites where EAB would most likely appear (i.e.

campgrounds due to importation of firewood). In addition, we made every effort to se-

0 10 20 30 40 50 60 70

Percent of Total Timberland

F

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e

s

t

T

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Major Forest Types

Other

Maple-Beech

Elm-Ash-Cottonwood

Oak-Hickory

II. Forest Health Issues: An Overview

2014 ILLINOIS FOREST HEALTH HIGHLIGHTS

Arthropod Pests: Overall, the 2014 growing season was relatively quiet with no ser ious ar -

thropod pest outbreaks, The one exception was the on-going infestations of Gouty Oak Gall

(GOG) on pin and shingle oaks (Quercus palustris and Q. imbricaria) in central, western, and

southern Illinois.

Gouty Oak Gall (GOG) Gouty oak gall (GOG) is a woody gall that forms on small twigs and branches of scarlet, red, pin, and black oaks (Quercus spp). The tiny native wasps, Callirhytis cornigera and C. quercuspunctata are responsible for forming the galls (Figures 3 and 4) (10).

Like most gall-forming wasps, their lifecycles can be rather complex and complicated and GOG is no excep- tion. Adults emerge in May and June, and lay eggs in major veins of oak leaves. GOG larvae form blister-like galls with adults emerging in July. After mating, the adult female lays eggs in young oak twigs. Young GOG’s appear as small, brown marbles which grow to two inch diameter brown galls. Later, adults emerge from the gall completing the two-year lifecycle. (Figures 3 and 4).

Galls can be physically removed on small trees in the northern part of the insect’s range (northern Illinois), but in southern Illinois, galling can be quite heavy and pruning may not be practical especially on large trees. Heavy galling can cause death of twigs and branches, but generally does not kill a mature, healthy tree (10).

As in 2013, heavy galling was observed again in 2014 along the I-57 corridor south of I-70 (Effingham, Illinois) as far south as the Dixon Springs area; between the I-57 and I-55 corridors from the Shawnee National Forest (SNF) north to I-70; and west from Springfield along I-74 to the Mississippi River. Heavy GOG popu- lations and tree death were observed in south-central Illinois (Eldon-Hazlett and S.A. Forbes State Parks) as well as in the Springfield, Illinois area. GOG-affected trees were in all stages of decline from newly infested trees to dead trees. Stress agents, such as drought, soil compaction, and poor drainage are probably the predis- posing agents for extensive dieback and death of pin oaks in south central Illinois, but death of individual branches by GOG was evident.

Figure 3. Heavy infestation of GOG Figure 4. Close up of GOG

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Plant Diseases:

Foliar, root rot, vascular, decline, and canker diseases. Overall, disease incidence was more typical for

2014. Near normal spring temperatures and abundant summer precipitation was favorable for most common

foliar diseases. Stress related diseases like Cytospora, Botryosphaera, Thyronectria, and Fusarium cankers,

oak wilt, and white pine decline were at normal levels. Phytophthora root rots were present probably due to

overwatering, poor drainage, and wrong plant siting. Phomopsis and Pestilotia tip blight of juniper and ar-

borvitae was observed statewide (1, 11)

Ash Decline and Dieback. Considerable ash (Fraxinus spp.) decline (both green and white ash) contin-

ued to be observed along the I-57 corridor south of I-70 to extreme southern Illinois (Dixon Springs area). De-

clining ash were also observed later in the season (July-August) along the I-64 corridor from south central Illi-

nois (Mt. Vernon area) west to the East St. Louis, IL. Most trees showed thinning canopies and dieback.

Death was also a common symptom. Trees were examined periodically throughout the summer, but there was

no evidence of EAB. This trend has been going on since 2008 and may be caused by ash decline and/or ash

yellows. Luley, et al. (1994) documented an outbreak of ash yellows in this geographic area.

More specifically, ash decline continued to appear in east central Illinois (Kickapoo S.P.) in July and August.

Ash decline was also observed in other areas of east central and southern Illinois (Fox Ridge, S.A. Forbes, and

Wayne-Fitzgerrell S.P.’s).

Pine Decline. IDNR distr ict foresters repor ted cases of white pine (Pinus strobus) decline statewide

particularly in western Illinois. In addition, dying and dead Scots (P. sylvestris) and Austrian (P. nigra) pines

were common, in both urban and forested areas. Individual trees were not specifically examined, but most

contain evidence of bark beetles and Carolina pine sawyer beetles, and probably died of pine wilt disease. The

droughts and hot weather of 2010 and 2011 followed by the severe and extreme 2012 drought continue to pre-

disposed these trees to the above pests and diseases.

Oak Decline. In addition to oak trees infested with GOG, drought effects were spotty. Chronoic oak

declind and some mortality was reported in central and western Illinois. Western Illinois has been under an

extended drought for the last number of years. Missouri also reported similar observations in eastern Missouri

adjoining portions of Illinois. Drought stressed oaks will be susceptible to Armillaria root rots, oak borers and

bark beetles.

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III. Exotic Pests

The emerald ash borer (EAB) continues to spread throughout Illinois particularly to the west and south. Seven (7) new positive finds for 2014 include Logan, Menard, Peoria, Perry, Sangamon, Tazewell, and Williamson counties. Five (5) additional counties are considered “at risk”, Christian, Franklin, Fulton, Jef- ferson, and Mason counties. In addition, EAB has been confirmed in three state parks (Rock Cut, White Pines, and Shabbona). Presently the IDA-EAB quarantine covers 61 of 103 Illinois counties (refer to Fig- ure 5). In 2014, purple and green Lindgren funnel traps (LFT’s) were deployed at 60 sites in Illinois state

parks forests, natural areas, forest pre- serves, and on private property of forest landowners. The emerald ash borer (EAB) is a phloem feeding wood boring insect that kills its host by destroying the vascular system of the tree. Unlike many other borers, EAB has the capability to attack both healthy and stressed ash trees.

Asian Long-horned Beetle (ALB). To date, no new sightings of ALB have been discovered. The original ALB in- fested areas are no longer under quaran- tine and the Illinois quarantine is now lift- ed since ALB has not been found since 2007. Visual surveys were conducted throughout Illinois.

Brown Marmorated Stink Bug (BMSB). This newest exotic insect pest was found in Illinois in Cook and Kane counties as early as 2010. This insect has a broad range host including tree fruits, vegetable, and woody landscape plants (3). To date, the BMSB has been found in 14 counties in Illinois primarily in NE, central, and SW Illinois. Five new coun- ties were added to the list in 2013 (15).

Figure 5. 2014 EAB Quarantine Map -New Finds

Viburnum Leaf Beetle (VLB). As r epor ted in the 2009 For est Health Highlights (FHH), the vibur - num leaf beetle (VLB) was found in 2009 in an urban Cook county landscape. The viburnum leaf beetle feeds on a variety of commonly planted viburnums and has the potential to become a major pest of these ubiquitous woody landscape plants. The VLB has added to the forest health watch list.

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Chinese Long-horned Beetle (CLHB). Another invasive long-horned beetle, Hesperophanes cam pestris; synonym Trichoferus campestris and similar to ALB appeared for the first time in 2009 near O’Hare airport and in Crawford county in east central Illinois (Figure 6). Its arrival at O’Hare is not surprising since it is a major point of entry, but the east central Illinois find is unsettling. The CLHB was captured near a pallet- making plant which is consistent with the movement of infested green wood and wood products. CLHB has also been found near Minneapolis, MN and in Quebec, Canada. The insect is originally from Asia and parts of Eastern Europe and spreads through movement of infested wood. It has a similar life cycle as the Asian long- horned beetle (ALB) and causes similar damage to trees. Preferred hosts of the CLHB are presented in Table 1 (9). In cooperation with APHIS, an intensive trapping, effort using 12 Unit LFT’s, was conducted in 2014 in 60 sites including state parks, forests, natural areas, and county forest preserves.

Table 1. Preferred hosts of the Chinese long-horned beetle (12)

Apple Mulberry Maple Birch Beech Ash Locust Walnut Larch, Fir Cedar Oak Willow Elm Cut wood of spruce and pine.

Figure 6. Adult Chinese Long-horned Beetle

Thousand Cankers Disease of Walnut (TCD) To date, neither the WTB nor TCD has been found in Illinois. Beginning in ear ly summer , 2014, four unit LFT’s were deployed along with a newly developed pheromone for detection of the walnut twig beetle (WTB). Traps were placed at sites including 60 state parks, forests, natural areas, county forest preserves, pri- vate woodlots, and wooded areas near mills (Figure 7). In addition to trapping, visual assessments of declin- ing walnut trees, and documentation of walnut plantings and walnut natural stands were conducted and devel- oped.

Sud atta woo can dea plin toco 201 Stre

Dut bee and ed b Mor tinu leve

Oak llin tree 201 ous trib pre-

Figure 7. Distribution of LFT’s for 2014

den Oak Death (SOD). SOD is a deadly disease that cks primarily oaks, but also rhododendron, and other dy ornamental trees and shrubs. The fungus causes kers on stems contributing to plant decline and eventual th. Beginning in spring, 2012, a stream baiting sam- g program was conducted as per the USDA-SOD pro- l. Another sampling period (October – November, 2) was conducted and no SOD inocolum was found. am baiting sampling was not conducted in 2014.

ch Elm Disease (DED). This vascular wilt disease has n with us for decades and continues to kill American red elms throughout Illinois. Based on reports provid- y the University of Illinois Plant Clinic (UIPC) and ton Arboretum Plant Clinic (MAPC), DED cases con- e to be a problem and levels were comparable to 2013 ls (1, 11).

Wilt (OW). The dreaded oak wilt is found in every

I ois county and has become a major urban and forest disease. Reports for 2012 by the UIPC indicate that 2 OW disease incidence was higher compared to previ- years (11). It is very likely, that the 2012 drought con- uted or even accelerated the development of OW in disposed trees.

Verticilium Wilt (VW). This very ubiquitous and oppor-

tunistic vascular wilt fungus was common in 2014 and at levels seen in previous years. Flooding and drought over the last seven years including the severe 2012 drought has and will continue to pre-dispose woody plants to VW. Sugar maple, red maple, ash, smoketree, Japanese maple, saucer magnolia, and three-flowered maple are just a few examples of VW susceptible hosts (3).

Bacterial Leaf Scorch (BLS). Bacterial leaf scorch resembles abiotic scorch, but is caused by a bacterium, Xylella fastidiosa (Figure 8). It is thought to be spread by leafhoppers and spittlebugs (Figure 9). Tree hosts include elm, hackberry, maple, mulberry, oak, sweetgum, sycamore, and planetree (Table 2) (5). Since 1999, the UIPC records show that BLS has tested positive in 10 Illinois counties stretching from Jefferson, Madison, and St. Clair counties in southern Illinois through parts of central Illinois (i.e. Sangamon, Champaign, Douglas -Moultrie, Iroquois), north to Cook and DuPage counties, and to Jo Daviess county in extreme northwest Illi- nois (11). With the exception of Champaign county with 40 positive samples, the remaining 9 counties have had 1-3 positive cases confirmed. In terms of hosts, BLS has been found in bur, northern red, pin, white, swamp white, and shingle oaks from 1999-2008. In 2008, BLS was found in seven oak positives including northern red, swamp white, pin and several unidentified oak species. Eleven BLS samples submitted in 2010 to the MAPC. Of the 11 samples, two were positive, one inclusive and eight were negative (1). The positives were found on oaks growing in DuPage and Cook counties.

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Historically, in 2011, a total of 22 trees were tested for X ylella fastidiosa. One sample, taken from an Ameri- can elm (U. americana), tested positive (Cook county), and six were elevated and inconclusive. Eleven (11) samples were taken from trees growing at The Morton Arboretum. Additional samples were received from western and northwestern suburbs of Chicago, and western Illinois, but were negative (1). Reports received from the UIPC indicate BLS symptoms were more pronounced in 2012 probably due to drought stress. No new BLS positives were recorded for 2014

Figure 8. Bacterial leaf scorch symptoms Figure 9. Spittle bug

Table 2. Tree species known to be susceptible and not susceptible to BLS (5) Susceptible Species Non-Susceptible Species (Based on Observations)

American elm European black alder Gingko Northern catalpa Hackberry Kentucky coffeetree Red maple Amur cork tree Silver maple Chinese elm Sugar maple Sugar hackberry Black oak Shagbark hickory Bur oak Shellbark hickory English oak Pignut hickory Northern red oak Katsuratree Pin oak Littleleaf linden Swamp white oak Cucumbertree White oak Black maple American sweetgum Chinkapin oak American sycamore Sawtooth oak

Common sassafras Tulip tree Japanese zelkova

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IV. Plant Diseases

Bur Oak Blight (BOB). Bur oak leaf blight is a fungal disease that attacks bur oak (Quercus m acro- carpa) with severe symptoms occurring on Q. macrocarpa var. oliviformis (Figure 10). It has been found in Kansas, Nebraska, Minnesota, Iowa, Wisconsin, Illinois and Missouri. In 2011, BOB was found isolated from a tree in Winnetka, Illinois (north shore area of Chicago) and in 2012 from a single tree in Lake County, Illinois. No BOB samples were not received in 2014 and no new finds were recorded.

BOB is caused by the Tubakia sp fungus resulting in blighting of the tree over a period of years. It starts in the lower portions of the tree and moves upward. Leaf symptoms usually do not show up until late summer (Figure 11). Severely affected trees may die after protracted years of defoliation. Bur oaks growing in estab- lished savannahs and upland areas appear to be more vulnerable. Oaks growing in bottomlands and/or dense forests appear to be less affected (4,12).

Figure 10. BOB tree symptoms Figure 11. BOB foliar symptoms

Needle cast disease. T wo ver y common diseases affecting conifer s, R hizosphaera needle cast and Dip- lodia (i.e. Sphaeropsis) were present in 2014. Both of these fungal leaf diseases attack the needles of cone- bearing tree species causing premature needle cast or a browning and/or death of the growing tip, respective- ly. While not outright fatal, they stress the trees and reduce overall ornamental qualities and growth rates. Coupled with chronic drought, a deadly combination may result (1,11).

Stress-related canker diseases. Cytospora cank er of spr uce is definitely a str ess r elated disease par tic- ularly of Colorado blue spruce. Spruces are a common urban forest and landscape species. The cankers are initially found on the undersides of the branches and result from some type of stress. Spruce trees growing in urban environments are very prone to this canker. While not fatal, the cankers cause branches to die distal to the canker resulting in a loss of ornamental quality and landscape function (1). In addition, there has been an increase of Thyronectria canker on honeylocust and the honey locust borer in areas of northeast Illinois. It is anticipated that other cankers will make their appearance for some time into the future. (1).

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Hickory Decline. In r ecent year s, r epor ts of dieback and mor tality of hickor y have been r epor ted in ar - eas of the upper Midwest (Figure 12). Bitternut hickory (Carya cordiformis) and shagbark hickory (C. ovata) appear to be most affected. Symptoms include thinning canopies, dead branches, and eventually tree death (13).

Historically, death of hickory trees was attributed to the hickory bark beetle (Scolytus quadrispinosus) following droughts. Recent research seems to indicate that hickory decline may include a complex of biotic and abiotic factors such as bark beetles (X ylobiopsis basilaris and borers (A grilus otiosus), and the fungus Ceratocysis smalleyi. In some cases, Armillaria root rot fungus has been found and is associated with recently dead trees (13).

Hickory decline and dieback is most common in overstocked stands. Current management practices include sanitation by removing dead and dying trees to reduce bark beetle breeding habitat and insecticide applications to the trunk of individual trees. Widespread use of insecticides for forest stands would not be economical nor practical (13).

Figure 12. Hickory decline

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Heterobasidion spp of red pine. The fungus is a root and basal stem rotting fungus that

colonizes cut stumps and then moves through root systems to adjoining trees. The fungus eventually colonizes

the lower stem leading to wind throw and death of affected trees. In the Midwest, white, red, and jack pines

are most susceptible (Figure 13). Thinned and/or harvested pine stands are prone to this disease. Prevention is

the best approach. Treating freshly cut stumps with a fungicide along with and good sanitation and

stump removal are important management tactics.

Aerial and ground surveys from 1962 to 1971 by Hanson and Lautz confimed Heterobasidion annosum being

present in southern Illinois. Since 1971, there is no record of further H. annosum surveys. 2014 statewide

surveys did not indicate any new finds of Heterobasidion spp. in red pine.

Figure 13. Distribution of Heterobasidion annosum or irregulare in the Northeastern, USA

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V. Insect Pests

Bark Beetles (BB) and Wood-borers (WB). Ba r k beetles atta ck pr ima r ily str essed tr ees including both hardwoods and conifers. Prolonged drought or a variety of abiotic and biotic stresses may pre-dispose trees to bark beetle attacks.

Based on field observations and in conversations with green industry members and foresters, 2014 appeared to a “normal year” for bark beetle activity. No major bark beetle outbreaks were observed or reported. Due to extremely dry conditions in some regions of the state, trees are still stressed and may be attacked by bark bee- tles and/or borers. Weaken trees may lack the ability to fight off these attacks and succumb.

In addition, engraver beetles and the Zimmerman pine moth continue to be chronic problems for many of our urban forest conifer species particularly Scots, Austrian, and mugho pines. As above, both of these insect pests tend to attack stressed conifers growing on poor sites (poor drainage) along with drought stress, soil com- paction, construction damage, etc.

Expanding on 2011 trapping efforts, 12 unit LFT’s were placed in 60 state parks, forests, and natural areas, on private land, and near wood mills during the 2014. Identification of trap specimens are still being processed and identified at this time.

Fall Webworm (FWW) and Eastern Tent Caterpillar (ETC). Small scatter ed pockets of fall webwor m (FWW) and eastern tent caterpillar (ETC) nests were seen at state parks and forests in southeastern (Lincoln Trail S.P.) and southern Illinois (Lake Murphysboro and Pyramid S.P’s). Populations were comparable to pre- vious years.

Japanese Beetle (JB). J apanese beetle was evident thr oughout the state , but defoliation was spor adic and not nearly as extensive as in previous years. Minor Japanese beetle feeding damage (<20% defoliation) was observed in most locations.

Elm Flea Weevil (EFW). The Eur opean flea weevil (EFW ) (Orchestes alni) has been a pest in the upper Midwest since 2003, but has been in the U.S. since 1982. The EFW is a very tiny insect (1/16th inches long) with the characteristic long snout. (Figure 14). Adults are reddish-brown with black heads. Adult EFW’s emerge in May and early June and begin feeding on young leaves chewing small holes in the leaf (Figure 15). Adult females lay eggs and the young larvae begin mining the leaf-tip eventually becoming a blotch-like mine. Larvae pupate within the leaf and emerge as a adults in mid to late summer. Adults over winter in under loose bark and in litter under infested trees (2). EFW feeding damage should not be confused with the elm leaf min- er (K aliofenusa ulmi) which is a blotch-mining sawfly. While the adult elm leafminer (ELM) emerges about the same time as the EFW there are subtle differences in larval feeding and biology. ELM larvae typically

Figure 14. Adult flea weevil Figure 15. Adult flea weevil feeding damage

form blotch-like mines throughout the leaf in contrast to the leaf tip mines associated with EFW larvae. Also, by mid-June, mature ELM larvae drop from the leaf and enter the soil to pupate. Adult emergence does not occur until the following spring with one generation per year.

Larval and adult feeding is usually considered an aesthetic issue, but coupled with heavy Japanese beetle feed- ing damage, preferred hosts can be completely defoliated by mid to late summer.

Research conducted at The Morton Arboretum (7, 8) and by Condra et al. (2010) indicate that U. pumila (Siberian elm) and ‘Homestead’ elm are the most susceptible to EFW feeding damage. In addition, long term field feeding preference studies conducted at The Morton Arboretum have indicated that elm hybrids with Siberian elm and U. carpinifolia parentage are strongly preferred by EFW (8). Refer to Table 3 for a listing of highly preferred hosts and host preference by geographic origin.

Table 3. Summary of elm flea weevil (EFW) medium to heavy feeding damage on elms (Ulmus spp) and

very low to low feeding damage, and by geographic origin (The Morton Arboretum (2004-2009).

Elm Biotype Elm Biotype

(Medium to Heavy) (Very Low to Low)

U. laevis U. propinqua var. suberosa

U. Morton Glossy ‘Triumph’ U. glabra

U. davidiana var. manshurica U. alata

U. americana f. pendula U. macrocarpa

U. lamellose U. thomasii

U. castaneifolia U. crassifolia

U. foliaceae U. parvifolia var. coreana

U. procera U. americana ‘Moline’

U. berganniana U. ‘Morton Plainsman x U. parvifoia

U. pumila 13 U. japonica x U. wilsoniana

VI. Weather/Abiotic Related Damage

The 2014 winter was characterized by much below normal temperatures with temperatures 6-10°F across most of Illinois. The winter started with near to above normal precipitation, but December was rather dry for much of Illinois (<75% of normal). Above normal precipitation prevailed from January to March with above normal snowfall. Most areas of the state experienced the most severe winter in 30 years and the 8th coldest for the region. Snowfall ranked in the top five for Illinois and other Midwestern states. For example, Chicago received 67.4 inches, making it the third highest on record. (14)

As spring 2014 approached, there was considerable concern about flooding due to heavy snow pack and deep frost (2-3 feet) in the soil. As it turned out, ideal snow melt conditions occurred and only minor flooding oc- curred due to cooler than normal spring temperatures (2-4°F below average in northern Illinois) and near nor- mal temperatures in April and May. Below normal precipitation occurred in western Illinois and was classified as abnormally dry to moderate drought based on the U.S. Drought Monitor. Summer, 2014 was quite pleasant with record cool for July (2nd coolest in Illinois) over much of the Midwest. June and August were slightly warmer than normal with a wet June (9th wettest for Illinois) and August. The cooler temperatures and ade- quate rainfall helped plants recover from the previous severe drought of 2012 and dry weather of July and Au- gust 2013 (14).

Aerial flyovers of the northern third of Illinois and extreme southern Illinois (Cache River Area) indicated Illi- nois forests were healthy, overall, with no obvious pest, disease, or abiotic problems.

DIAGNOSTIC TRAINING CLINICS: A series of diagnostic training and EAB management workshops were conducted throughout Illinois in 2014. Attendees included commercial and municipal arborists, IDNR district foresters, consultants, master gardeners, allied members of the green industry, and natural resource managers. Workshop participants received instruc- tion on proper pest and disease identification, diagnosis, and sampling techniques. Additional topics included updates on EAB management, TCD, BLS, BOB, common arthropod pests, and abiotic diseases.

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VII. References

1. Adams, S., 2012. The Morton Arboretum Diagnostic Plant Clinic and Plant Health Care Reports. The Morton Arboretum, Lisle, Illinois.

2. Condra, J., C. Brady, and D.A. Potter. 2010. Resistance of landscape suitable elms to J apanese bee- tle, gall aphids, and leaf miners, with notes on the life history of Orchestes alni and A grom yza aristata in Ken- tucky.

3. Gill, C. 2010. Plant Health Progress. Pennsylvania State University (PSU) (17 October 2010).

4. Harrington, T. 2011. It looks like bur oak blight (BOB) really isn’t new. Iowa State University, Horticul- ture Home Pests News. February, 2011

5. Hartman, J. 2007. Bacterial leaf scorch. P PFS-OR-W-12. University of Kentucky Cooperative Exten- sion Service

6. Luley, C., M. Mielke, J. Castello, J. Carlson, and J. Appleby. 1994. Ash cr own condition and the in- cidence of ash yellows and other insects and diseases in Illinois, Iowa, Missouri, and Wisconsin. Plant Dis- ease. 76: 1209-1212.

7. Miller, F. 2000. Insect r esistance of elm genotypes. [Pr oceedings of the Fir st Inter national Elm Con- ference.] Entitled: The Elms: Breeding; Conservation, and Disease M anagement. ed. C. Dunn. pp. 137-154.

8. Miller, F. (Unpublished). Obser vations on the pr efer ence and susceptibility of elms (Ulm us spp.) for feeding by the elm flea weevil.

9. Minnesota Department of Agriculture. 2011. Invasive pest alert: Chinese longhorned beetle.

10. Nixon, P. 2001. Gouty and horned oak galls. University of Illinois, Home, Yard, and Garden Newslet- ter. Urbana-Champaign, Illinois.

11. Pataky, N. and S. Porter. 2008-2012. Woody Plant Disease Updates. University of Illinois Plant Clinic (UIPC). Urbana, Illinois.

12. Pokorny, J. and T. Harrington. 2011. Bur oak blight. Pest Alert-NA-PR-02-11. USDA Forest Ser- vice.

13. Wisconsin DNR. 2007. Hickory dieback and mortality in Wisconsin.

14. Midwest Regioal Quarterly Climate Impacts and Outlook for Mar ch, J une, and September , 2014. NOAA.

15. Weinzierl, R. 2013. Illinois State Fr uit and Vegetable Newsletter .

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PLEASE NOTE: The data presented in this summary are not to be considered to be comprehensive nor all inclusive studies. The narrative report- ed here is based on visual and observational surveys by Dr. Fredric Miller, IDNR Forest Health Specialist, IDNR Forest Health field technicians, IDNR district foresters, Stephanie Adams of The Morton Arboretum Plant Diagnostic Clinic, informal conversations with consultants and members of the green, natural resources, and forest industries.

Project was funded in whole or in part through a grant awarded by the USDA, Forest Service, Northeastern Area State and Private Forestry. The USDA is an equal opportunity provider and employer.